Narrated Jabir bin `Abdullah:
that he heard the Prophet (ﷺ) saying, "The Divine Inspiration was delayed for a short period but suddenly, as I was walking. I heard a voice in the sky, and when I looked up towards the sky, to my surprise, I saw the angel who had come to me in the Hira Cave, and he was sitting on a chair in between the sky and the earth. I was so frightened by him that I fell on the ground and came to my family and said (to them), 'Cover me! (with a blanket), cover me!' Then Allah sent the Revelation: "O, You wrapped up (In a blanket)! (Arise and warn! And your Lord magnify And keep pure your garments, And desert the idols." (74.1-5)
Narrated Yahya bin Abi Kathir:
I asked Aba Salama bin `Abdur-Rahman about the first Sura revealed of the Qur'an. He replied "O you, wrapped-up (i.e. Al Muddaththir)." I said, "They say it was, 'Read, in the Name of your Lord Who created,' (i.e. Surat Al-`Alaq (the Clot)." On that, Abu Salama said, "I asked Jabir bin `Abdullah about that, saying the same as you have said, whereupon he said, 'I will not tell you except what Allah's Messenger (ﷺ) had told us. Allah's Messenger (ﷺ) said, "I was in seclusion in the cave of Hiram', and after I completed the limited period of my seclusion. I came down (from the cave) and heard a voice calling me. I looked to my right, but saw nothing. Then I looked up and saw something. So I went to Khadija (the Prophet's wife) and told her to wrap me up and pour cold water on me. So they wrapped me up and poured cold water on me." Then, 'O you, (Muhammad) wrapped up! Arise and warn,' (Surat Al Muddaththir) was revealed." (74.1)
Narrated Yahya:
I asked Aba Salama, "Which Sura of the Qur'an was revealed first?" He replied, "O you, wrapped-up' (Al-Muddaththir)." I said, "I have been informed that it was, 'Read, in the Name of your Lord who created (i.e. Surat Al-Alaq)...similar to the narration related by `Ali bin Al-Mubarak, 444 above).
Yahya reported: I asked Abu Salama what was revealed first from the Qur'an. He said:" 0, the shrouded one." I said: Or" Recite." Jabir said: I am narrating to you what was narrated to us by the Messenger of Allah (ﷺ). He said: I stayed in Hira' for one month and when my stay was completed, I come down and went into the heart of the valley. Somebody called me aloud. I looked in front of me, behind me, on the right of my side and on my left, but I did not see any body. I was again called and I looked about but saw nothing. I was called again and raised my head, and there on the Throne in the open atmosphere he, i. e. Gabriel (peace be upon him) was sitting. I began to tremble on account of fear. I came to Khadija and said: Wrap me up. They wrapped me up and threw water on me and Allah, the Exalted and Glorious, sent down this: you who are shrouded! arise and deliver warning, your Lord magnify, your clothes cleanse."